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1.
Xiao-Ying Bie 《Biocatalysis and Biotransformation》2016,34(3):89-98
The effects of important production variables on the biotransformation of sucrose by immobilized cells of Phaffia rhodozyma were investigated. Cell concentration had negative effect on the maximum concentration of neokestose and the optimal concentration was 16?g/l (calculated by dry weight). The concentration of sucrose had a positive effect on the maximum concentration of neokestose within 1.170?mol/l. Elevating the reaction temperature increased the reaction rate but decreased the maximum concentration of neokestose. Sugar cane juice could be used as an inexpensive substrate for neokestose production. Additionally, a 30-d continuous neokestose production was found feasible in a packed bed reactor, indicating that the cell immobilization with chitosan-coated alginate has the potential for industrial production. 相似文献
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To optimize biomass and carotenoid production by Phaffia rhodozyma in pH-stat cultures, two methods of feeding glucose were studied. In the first method, which is comparatively simple to operate, the glucose feeding set point (pH 5.02) was higher than the culture pH (5.00) and P. rhodozyma grew at a low specific growth rate (=0.055 h–1). In the second method, the glucose feeding set point (pH 4.98) was lower than the culture pH (5.00) and the yeast grew at a specific growth rate of =0.095 h–1. With the second method of glucose feeding, which is more complex and in order to prevent overfeeding of glucose, a time interval was added to the control strategy of the glucose pump and allowed to expire before the next dose of glucose was added. The length of the time interval affected biomass and carotenoid production. A critical time interval (Tc) was defined. In pH-stat cultures of P. rhodozyma, it was found that if the time interval was set longer than the critical time interval, the yeast did not grow. 相似文献
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Addition of ethanol (0.2%) to cultures of the yeast Phaffia rhodozyma increased the specific rate of carotenoid production [(carotenoid)(cell mass)−1(time)−1]. The incremental increase in carotenoid synthesis with ethanol was highest in carotenoid-hyperproducing strains. Ethanol
increased carotenoid production when it was added at various points during the lag and active growth phases. Ethanol increased
alcohol dehydrogenase and hydroxy-methyl-glutaryl-CoA (HMG-CoA) reductase activities. Our results indicate that increased
carotenoid production by ethanol is associated with induction of HMG-CoA reductase and possibly activation of oxidative metabolism.
Received 24 December 1996/ Accepted in revised form 27 May 1997 相似文献
4.
During fermenter cultivation of Phaffia rhodozyma on a grape juice medium, the presence of glucose initially delayed fructose utilization, although fructose was consumed before glucose depletion. Total pigment and astaxanthin production were growth associated and reached maximum values of 15.9 g/ml and 9.8 g/ml, respectively, after depletion of the carbon source. The total cellular pigment and astaxanthin content increased during the stationary growth phase due to a decrease in biomass, reaching final values of 2120 g/g and 1350 g/g, respectively, without the volumetric concentration in the culture changing. The final cell yield was 0.33 g/g sugar utilized. High sugar concentrations in shake-flasks as well as O2 limitation decreased the astaxanthin content of the cells. Addition of yeast extract to a grape juice minimal medium markedly increased the maximum specific growth rate, total pigment and astaxanthin content of the cells. An excess of ammonia decreased the intracellular astaxanthin content, which reached a maximal value in cultures with no residual glucose or ammonia.The authors are with the Department of Microbiology and Biochemistry, University of the Orange Free State, P.O. Box 339, Bloemfontein 9300, South Africa; 相似文献
5.
Effect of acetic acid on astaxanthin production by Phaffia rhodozyma 总被引:10,自引:0,他引:10
Summary Low concentrations of acetic acid decreased the growth rate of and astaxanthin production by Phaffia rhodozyma on glucose, with growth completely inhibited by 2 g acetic acid/l. Using H2SO4 for pH control after sugar depletion caused a decline in the biomass concentration, whereas using acetic acid as titrant resulted in an increase in the biomass with a high astaxanthin content of 1430 g/g cells. An extended culture with a continuous glucose feed failed to maintain a high astaxanthin content. 相似文献
6.
L. Rubinstein A. Altamirano L. Ducrey Santopietro M. Baigorí L. C. de Figueroa 《Biotechnology Techniques》1996,10(12):929-932
Summary The transformation of Phaffia rhodozyma by electroporation was better than the one by the lithium chloride (LiCl) or spheroplast transformation methods. The influence of several parameters on transformation efficiency was studied. Electroporation conditions of 1200 Volts, 50 Farads and 2000 Ohms were proved successful. A maximum of 1.5 × 103 transformants per 100 ng of DNA was reached. 相似文献
7.
This study aimed to evaluate the influence of magnetic fields (MF) on inoculum cultivation and carotenoid production by Phaffia rhodozyma. The application of MF in the inoculum culture was evaluated (0 m T – control and 30 m T). Cellular concentration increased by 12.8 % after 24 h-culture with MF application compared to the control assay, and this was the best alternative for the preparation of inoculum. Different intervals of MF application were evaluated over 168 h. The highest volumetric carotenoids concentration was achieved by applying MF throughout cultivation, with values of 1146.39 ± 26.18 μg L−1 and carotenoid productivity of 11.94 ± 1.11 μg L−1 h−1 in 96 h. As a result, carotenoid production increased by 59.4 % and carotenoid productivity by 99.3 %. This study is one of the first to consider MF application in carotenoid production using P. rhodozyma as a viable and low-cost alternative for carotenoid production in a shorter cultivation time. 相似文献
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响应面法对红法夫酵母合成虾青素主要影响因素的优化 总被引:1,自引:0,他引:1
在单因素试验确定了红法夫酵母生物合成虾青素培养基组份的基础上,用响应面法对其浓度进行优化。首先用分式析因设计评价了培养基的各组份对虾青素产量的影响,并找出主要影响因子为蔗糖和酵母粉,二者分别达到了极显著和显著水平。用最陡爬坡路径逼近最大响应区域后,运用旋转中心复合设计及响应面分析,确定了主要影响因子的最佳浓度。其中,蔗糖的最佳浓度为49.8g/L,酵母粉的浓度为9.6g/L。菌株在优化培养基中的虾青素产量为9861μg/L,比优化前增加了近1倍。 相似文献
10.
R D Medwid 《Journal of industrial microbiology & biotechnology》1998,21(4-5):228-232
The ploidy of the red yeast Phaffia rhodozyma was evaluated using flow cytometric analyses of propidium iodide- stained cells and mutagenic inactivation kinetics. Our
findings suggest that Phaffia rhodozyma is not haploid. Auxotrophic strains were generated at a high frequency following treatment of mutagenized cells with a combination
of benomyl and ethyl acetate. Studies of an auxotrophic mutant using flow cytometry and UV inactivation indicated possible
chromosome loss to an aneuploid state.
Received 21 June 1998/ Accepted in revised form 25 September 1998 相似文献
11.
Díaz A. Sieiro C. Blanco P. Villa T.G. 《World journal of microbiology & biotechnology》2002,18(8):811-812
The effect of different sesquiterpenes on carotenoid synthesis in Phaffia rhodozyma was studied. Addition of squalene to the culture medium resulted in a decrease in the echinenone and trans-astaxanthin concentrations, whereas -carotene remained unchanged. The role of squalene as an inhibitor of ketocarotenoid synthesis in Ph. rhodozyma is discussed. 相似文献
12.
红发夫酵母的生物学特性 总被引:2,自引:0,他引:2
红发夫酵母以单细胞为主,有时能形成假菌丝。菌落因菌体产生虾青素等类胡萝卜素而呈红色,类胡萝卜素均匀地分布于细胞脂质中。红发夫酵母为专性好氧菌,细胞产生类胡萝卜素需要大量氧气。葡萄糖和蔗糖为最佳碳源,酵母膏是最佳氮源。红发夫酵母具克拉布特里效应(Crabtree)。红发夫酵母生长温度范围为4-27℃,属于兼性嗜冷的低温型微生物。最适生长pH为6.0,色素形成的最适pH为5.0。 相似文献
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《Journal of Fermentation and Bioengineering》1993,75(6):466-469
Phaffia rhodozyma strains were treated with the mutagenic agent NTG several times and plated onto yeast-malt agar containing β-ionone as a selective medium. One of the NTG-treated strains (NCHU-FS301) produced considerably more astaxanthin than the parent CBS-6938 (strain NCHU-FS301 produced 1515.63 μg/g and CBS-6938 565.08 μg/l). When the kinetic parameters of the specific growth rate (μ) and specific astaxanthin productivity (qp) were used to judge the association between growth behavior and product formation, NCHU-FS301 was shown to be a more positive growth-associated fermentation type than the parent strain. A study of the effects of the carbon source on red pigment formation revealed that glucose could support the highest total astaxanthin production (7809.3 μg/l). Yeast extract was the best nitrogen source in supporting the highest total astaxanthin formation (8637.5 μg/l). When mixed nitrogen sources were used, a mixture of yeast extract, beef extract, and potassium nitrate (1:1:1) supported more pigmentation (8052.6 μg/l) than the other mixtures tested. Astaxanthin-overproducing mutants could be useful in providing a natural source of astaxanthin for the aquacultural industry. 相似文献
16.
Ágnes Nagy Nándor Garamszegi Csaba Vágvölgyi Lajos Ferenczy 《FEMS microbiology letters》1994,123(3):315-318
Abstract Electrophoretic karyotypes of strains from the astaxanthin-producing yeast Phaffia rhodozyma have been established. Intact chromosomal DNA molecules released from protoplasts were separated by orthogonal field alternation gel electrophoresis (OFAGE) and contour clamped homogeneous electric field (CHEF). Both small and large chromosomal DNA molecules were resolved simultaneously by optimizing the running conditions. Electrophoretic karyotypes among the Phaffia isolates examined differed significantly. Seven to thirteen chromosomal bands, ranging in size from 0.83 Mb to 3.50 Mb, were resolved, giving total genome sizes of about 15.4 to 23.2 Mb. Ribosomal DNA has been assigned to chromosomal bands using a heterologous gene probe. 相似文献
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Increased astaxanthin production by a Phaffia rhodozyma mutant grown on date juice from Yucca fillifera 总被引:1,自引:0,他引:1
J Ramírez M L Nuñez R Valdivia 《Journal of industrial microbiology & biotechnology》2000,24(3):187-190
The wild strain and the astaxanthin-overproducing mutant strain 25–2 of Phaffia rhodozyma were analyzed in order to assess their ability to grow and synthesize astaxanthin in a minimal medium composed of g L−1: KH2PO4 2.0; MgSO4 0.5; CaCl2 0.1; urea 1.0 and supplemented with date juice of Yucca fillifera as a carbon source (yuca medium). The highest astaxanthin production (6170 μg L−1) was obtained at 22.5 g L−1 of reducing sugars. The addition of yeast extract to the yuca medium at concentrations of 0.5–3.0 g L−1 inhibited astaxanthin synthesis. The yuca medium supported a higher production of astaxanthin, 2.5-fold more than that observed
in the YM medium. Journal of Industrial Microbiology & Biotechnology (2000) 24, 187–190.
Received 14 July 1999/ Accepted in revised form 02 December 1999 相似文献
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Optimization of astaxanthin production by Phaffia rhodozyma through factorial design and response surface methodology. 总被引:6,自引:0,他引:6
Sequential methodology based on the application of three types of experimental designs was used to optimize the astaxanthin production of the mutant strain 25-2 of Phaffia rhodozyma in shake flask cultures. The first design employed was a factorial design 2(5), where the factors studied were: pH, temperature, percent of inoculum, carbon and nitrogen concentrations, each one at two levels. This design was performed in two medium types: rich YM medium and minimal medium, based on date juice (Yucca medium). With this first design the most important factors were determined (carbon concentration and temperature) that were used in the second experimental strategy: the method of steepest ascent was applied in order to rapidly approach the optimum. Finally, a second-order response surface design was applied using temperature and carbon concentration as factors. The optimal conditions stimulating the highest astaxanthin production were: 19.7 degrees C temperature; 11.25 g l(-1) carbon concentration; 6.0 pH; 5% inoculum and 0.5 g l(-1) nitrogen concentration. Under these conditions the astaxanthin production was 8100 microg l(-1), 92% higher than the production under the initial conditions. 相似文献